The present invention relates generally to a joint assembly and more specifically to a joint assembly having a boot seal which at least partially defines a chamber containing lubricant. Ball joint assemblies commonly include a housing having a socket chamber in which a ball end portion of a stud member is disposed. A shank portion of the stud member extends axially out of the housing. A boot seal engages the housing and the shank portion of the stud member to prevent external environmental contamination from entering the housing. The boot seal cooperates with the housing and the stud member to form a chamber which holds lubricant, such as a suitable grease. In order to vent excessive lubricant pressure from the chamber, a slit has been provided in the boot seal to enable lubricant to be flow from the chamber. Unfortunately, external contaminants can enter the lubricant chamber through the slit in the side wall of the boot seal. In addition, the forming of the slit in the boot seal has required a separate operation and has added to the cost of the ball joint assembly. One known ball joint assembly having this construction is disclosed in U.S. Pat. No. 3,208,290 issued Sep. 28, 1965 and entitled "Ball Joint Purgeable Seal Means".